Catalyst for selective hydrogenation, its preparation process and application

Abstract

A catalyst for selective hydrogenation of alkynes and dienes, its preparation process and application. The catalyst has an inorganic oxide support, a major active component palladium, and a Group IB metal promoter. The active components are uniformly distributed in the catalyst body within the thickness between the support surface and the depth of more than 300 mum. The catalyst of the present invention has high activity, high selectivity, ability to resist sulfur and arsenic poisoning. The catalyst is particularly applicable to C2-C3 fraction with any concentrations of hydrogen and CO.

What is claimed is:  
     
       1. A selective hydrogenation catalyst comprising: 
       an inorganic oxide support selected from the group consisting of alumina, titania, and a chemical composite of alumina and titania;  
       a major active component palladium of a content of about 0.002-1.0% based on the total weight of the catalyst; and  
       at least one promoter selected from Group IB metals, the mole ratio of palladium to the Group IB metal is in the range of about 1 to about 20;  
       wherein the major component palladium and the promoter are uniformly distributed together in the catalyst within the thickness between the support surface and the depth of more than about 300 μm.  
     
     
       2. The catalyst according to  claim 1 , wherein the content of alumina in the chemical composite of alumina and titania is about 1-99% by weight. 
     
     
       3. The catalyst according to  claim 2 , wherein the content of alumina is about 20-80% by weight. 
     
     
       4. The catalyst according to  claim 3 , wherein the content of alumina is about 40-60% by weight. 
     
     
       5. The catalyst according to  claim 4 , wherein the support comprises the following physical properties: bulk density of about 0.7-0.9 g/ml, pore volume of about 0.3-0.6 ml/g, specific surface area of about 10-60 m 2 /g, mean pore diameter of about 40-100 nm. 
     
     
       6. The catalyst according to  claim 1 , wherein the content of the major active component palladium is about 0.005-0.5 wt %. 
     
     
       7. The catalyst according to  claim 6 , wherein the content of the major active component palladium is about 0.01-0.05 wt %. 
     
     
       8. The catalyst according to  claim 1 , wherein the promoter is selected from the group consisting of Cu, Ag, and Au. 
     
     
       9. The catalyst according to  claim 1 , wherein the mole ratio of palladium to the Group IB metal is in the range of about 1-10. 
     
     
       10. The catalyst according to  claim 9 , wherein the mole ratio of palladium to the Group IB metal is in the range of about 1.0-5.0. 
     
     
       11. The catalyst according to  claim 1 , wherein the active component palladium and the promoter Group IB metal existing in the form of oxides in the support are reduced to fine alloy particles with a diameter of about 2-10 nm. 
     
     
       12. The catalyst according to  claim 1 , wherein the dispersion depth is within the thickness between the support surface and the depth of 500-1000 μm. 
     
     
       13. The catalyst according to  claim 1 , further comprising alkali metals and/or alkaline earth metals.